1. Field of the Invention (Technical Field)
The present invention relates to the field of plant removal and eradication, particularly with regard to removing the roots of plants. The present invention is an apparatus and method for the application below ground of fluids to plants and/or soil, in particular for applying pesticides and fungicides to roots being severed during the process of root plowing. This technology is useful on virtually any blade that is being drawn through the soil.
2. Background Art
Note that the following discussion refers to a number of publications by author(s) and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-à-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
There is an immediate need for a process to eradicate non-native dense tree and brush species from ecosystems, primarily riparian ecosystems. These non-native species are often able to out-compete native species of plants and trees. The non-native species usually consume more water, lowering the level of the lake or river and further damaging the entire ecosystem.
Once established, many dense tree and brush species are extremely difficult, if not impossible, to eradicate. There deep root zones and ability to quickly re-grow from roots renders cutting and shallow root plow methods ineffective. While different methods have been developed to control these species, none is entirely satisfactory.
The current process to remove Salt Cedar (Tamerix), for example, is:                1) Use a non-selective herbicide on the canopy applied by aircraft on larger, monolithic stands (arsenal and roundup combination);        2) Let it stand for up to two years for the herbicides to take effect, which usually results in about a 90% kill;        3) Utilizing heavy equipment, stack and burn dead material;        4) Root plow area being treated;        5) Root rake;        6) Stack and burn for the second time;        7) Retreat sprouts that were missed with the herbicide and mechanical treatment (the result at this point is an area in which about 98% of all vegetation has been eradicated); and        8) Revegetate area (pole plantings and seedings) back to native vegetation.This process is costly, takes an inordinate amount of time, and is not completely effective. Also, since the herbicide is applied non-selectively from the air, large amounts must be used, increasing the cost and the potential for harm to native plants, animals, and even human populations.        
While prior methods have been developed to place fluids and gases below ground level, no method currently in use is able to operate at great depths and apply herbicide directly to severed roots. The following is a discussion of several background patents.
U.S. Pat. No. 5,996,514, entitled “Apparatus and Method for Subsurface Application,” issued Dec. 7, 1999, to Arriola et al, describes a method of applying fluids to soil at depths of up to 12 inches. A plurality of shanks dig trenches in the soil, and a nozzle behind each shank delivers fluid into the trench. U.S. Pat. No. 5,558,471, entitled “Device for Injecting Chemicals into the Soil,” issued on Sep. 24, 1996, to Payne, describes a device that also sprays fluid into trenches at shallow depths, but uses discs and knives to cut the trenches. A belt keeps vegetation on the soil. While the Arriola and Payne inventions are useful for shallow application, they do not have the ability to effectively sever deep roots, or apply fluid to those roots.
U.S. Pat. No. 5,240,080, entitled “Adjustable Attachment for Mounting a Farming Tool on a Drawing Vehicle,” issued Aug. 31, 1993, to Bassett, et al, describes an apparatus for mounting a subsurface plow to a towing vehicle. An apparatus for placing fertilizer into the soil is also described, but it only operates at shallow depths.
U.S. Pat. No. 3,581,685, entitled “Device for Distributing Chemicals Beneath the Soil Surface and Conditioning Seed Beds,” issued Jun. 1, 1971, to Taylor, describes a subsurface plow with nozzles for fluid delivery. Dirt mover wings are included to remove soil from above the plow, so this device operates on the surface or at very shallow depths.
U.S. Pat. No. 6,167,821, entitled “Method and Apparatus for Fumigating Soil,” issued to Beggs Jan. 2, 2001, describes an apparatus for injecting gasses two to twelve inches into the soil. The apparatus digs trenches in the soil, injects the fumigant, and then seals the trenches and packs the soil to prevent escape of the fumigant.
U.S. Pat. No. 3,590,588, entitled “Process and Apparatus for Laying a Subterranean Film,” issued Jul. 6, 1971, to Draper et al, describes an apparatus for placing a sheet of plastic horizontally one to four feet below ground level. The sheet is drawn through the apparatus and then unfolded below ground level by the apparatus. Nozzles may be used to apply fluid to the sheet as it leaves the apparatus, but not to the soil itself.
U.S. Pat. No. 3,398,542, entitled “Subterranean Plow,” issued Aug. 27, 1968, to Hansen et al, describes an apparatus for placing an asphalt membrane below ground level. As the plow is drawn through the soil, asphalt is injected into a cavity formed by the plow.
U.S. Pat. No. 4,825,959, entitled “Fertilizer System,” issued May 2, 1989, to Wilhelm, describes a fertilizer distribution apparatus for use with a subterranean plow. Fertilizer distribution pipes are enclosed within a channel for protection, but are not integrated into the cutting blade.
U.S. Pat. No. 4,683,826, entitled “Subsurface Application of Chemicals,” issued Aug. 4, 1987, to Solie, et al, describes an apparatus and a method for applying chemicals to soil at depths of up to eight centimeters. A system of upwardly-pointing nozzles and supply manifolds is attached to the rearward edge of a subterranean plow, so that chemicals are applied to soil after it passes over the plow. Because this invention operates at shallow depths, it cannot apply fluids to deep root zones.
U.S. Pat. No. 6,276,463, entitled “Compacted Soil and Rock Raising Blade,” issued Aug. 21, 2001, to Hollimon, et al, describes a subsurface plow able to operate at depths greater than one foot, but the plow lacks a means to deliver fluids to the soil.
In summary, the prior art includes subsurface plows that apply fluids into the soil; however, they are designed to operate at or very close to the surface, with their primary application being the removal of weeds from agricultural land. Prior art methods are inadequate for the eradication of thick tree and brush species, which have root zones that are much deeper than the weeds that these devices were designed to eradicate.
What is needed is an apparatus that can severe thick roots deep below ground, and then apply herbicide selectively below ground to destroy any remaining roots all the while keeping the spray nozzles protected. Utilization of the method and apparatus of the present invention accomplishes this and provides a simple, effective, and inexpensive process.